Geology/History

The eastern portion of Botswana forms part of the Limpopo Mobile Belt (LMB) which represents a deep crustal section through an orogenic province between the Kaapvaal and Zimbabwe Cratons.

The Project occurs in highly deformed and metamorphosed Archean gneisses near the north margin of the central zone (CZ) of the LMB.  The CZ region is characterized by complex structural fold patterns accompanied by regional and cataclastic metamorphism with grades ranging from amphibolite to granulite facies and cataclastic tectonites.  

The deposits in the Project area are categorized as ortho-magmatic nickel-copper sulphide-type deposits.  They are hosted within amphibolite and understood as a tectono-metamorphically modified tholeiitic magma parents with an immiscible sulphide melt which has undergone all the phases of deformation that have affected the enclosing gneisses.  They form part of the Selebi-Phikwe belt of intrusions that also contain the Phikwe, Dikoloti, Lentswe, and Phokoje deposits.  

All mineralization horizons pinch and swell, are conformable to the gneissic foliation, and are hosted within or at the hanging wall contact of amphibolite with the gneissic country rocks.  Mineralization horizons range in thickness from very thin to over 20 m thick and are commonly one to three metres thick (deposit dependent).  Orientation follows country rock foliation, and the zones can dip moderately to steeply, and can extend from 150 m to over 2,000 m.

The principal sulphide minerals are pyrrhotite, chalcopyrite, and pentlandite which occur in massive, semi-massive, and disseminated form.  Pyrite occurs as localized overgrowth.  Magnetite occurs as rounded inclusions in massive sulphides and as later overgrowths.

Exploration in the Project area was initiated in 1959 by Bamangwato Concessions Limited (BCL) and included soil geochemistry, geological mapping, trenching, and diamond drilling over the then combined Selebi Phikwe area.  The Selebi and Phikwe discoveries were made in 1963 and 1967, respectively and a single mining lease was granted to BCL in 1967 covering both areas. 

Construction of the Phikwe processing plant began in 1970 concurrently with the sinking of the Phikwe No. 1 and Selebi No. 2 shafts. Close spaced geochemical surveys conducted as follow-up produced copper and nickel anomalies at Phikwe and Selebi and drilling was shifted to these areas.  Drilling at these targets continued until 1971 with the subsequent opening of the Phikwe open pit.  The concentrator began operations in 1973 at a rate of 6,000 tpd, and the capacity was increased to 10,000 tpd over time.  

In 1980, the Phikwe open pit was exhausted and the underground operations at Selebi #2 Shaft were phased in.  Production began at Selebi North No. 4 Shaft in 1990.

BCL operated the combined Selebi-Phikwe project from 1970 until its closure in 2016. 

Drilling was first conducted in 1964 prior to closely spaced geochemical sampling.  After completion of eight shallow wagon drill holes, drilling was suspended due to poor results, however, three of the holes indicated possible enrichment with depth.  

A year later in 1965, drilling resumed and confirmed the improvement of sulphide mineralization grades with depth. Drilling continued and by the end of 1971, drilling on the Selebi targets totalled 73 holes for 19,294 m.  Further surface exploration drilling continued at Selebi between 1980 and 1994 to confirm the down-dip and northerly continuation of the mineralization.

Since 2004, several exploration methods have been employed to generate targets for further examination.

A desktop study employing satellite image interpretation coupled with field mapping was completed by SRK over the Selebi-Phikwe project area.  The study generated 23 independent prospects, ten of which were located on the current Project claim area. SRK recommended specific follow up work including mapping, geochemical surveys, and ground electromagnetic surveys.  The follow up work, including VTEM, surface EM and Titan 24 DCIP/MT surveys, was commissioned and completed by several contractors between 2005 and 2010. The most prospective areas following this work were drill tested.  In 2009, the drill testing of a VTEM anomaly located between the Selebi and Selebi North shafts intersected Ni-Cu mineralization and led to a large drilling campaign to explore the new Selebi Central Zone. Surface drilling was also completed to test for down-dip extensions of the existing known deposits. Downhole EM surveys were completed in 2009 and 2010 but it is unknown if there were any follow-up of the results.